Bosch develops system that shuts off car engines when they are coasting

This site may earn affiliate commissions from the links on this page. Terms of use.

The combustion engines in all conventional automobiles run from the moment you switch them on until you shut them off at your destination. According to German engineering firm Bosch, about 30% of the idling in between can be eliminated without affecting the speed or acceleration of the car. It has even devised a system to make that happen.

Bosch’s system simply flips the engine off whenever the vehicle’s speed can be maintained by coasting. For example, if you’re driving on a gentle downward slope, the momentum of the vehicle is enough to keep you going. Then there is the long coast up to a stoplight before you apply the brake. As soon as your foot is off the gas, Bosch’s system could even decide to shut the engine off for a few seconds. This start-stop system would shut the engine off in all those instances, but would instantly restart it as soon as the gas or brake is tapped.

Early estimates place the fuel savings around 10% with the corresponding reduction in carbon emissions. This doesn’t quite match the lofty predictions for some other technologies, but the coasting engine design can be implemented in today’s cars with very little modification. It makes use of all the same sensors already being used in cars, so all it requires is a few additional components to ensure fast restarts when the accelerator or brake is activated.

The next generation start-stop technology could be of use in both European and American gasoline engines, diesel, and compressed natural gas vehicles in Asia. Bosch sees start-stop engines as a no-brainer for inclusion in future cars that will eventually be as common as air conditioning — so, just about universal.